The application generally relates to condensers in vapor compression systems. The application relates more specifically to a second heat exchanger for a condenser of a vapor compression system.
In some conventional condensers, condenser tubes may be used to circulate a fluid that can exchange heat with refrigerant vapor entering the condenser, causing the refrigerant vapor to condense to a liquid. Before the refrigerant liquid leaves the condenser, the refrigerant liquid may be further cooled by a second heat exchanger that includes tubes positioned in a component in the condenser. The component controls the flow of the refrigerant liquid over the tubes, which also circulate a fluid to exchange heat with the refrigerant liquid.
In many applications, only liquid refrigerant should enter the component, as vapor entering the component may decreases the efficiency of the second heat exchanger because the rate of convective heat transfer for the refrigerant in the vapor phase is much less than in the liquid phase. Further, allowing refrigerant vapor to enter the component may result in refrigerant vapor leaving the condenser, which may decrease the efficiency of the system, because a reduced amount of refrigerant liquid is provided to the remainder of the system.
To prevent refrigerant vapor from entering the component, the component can be submerged in a reservoir of refrigerant liquid that extends along the length of the condenser. The refrigerant liquid reservoir forms a liquid seal that prevents refrigerant vapor from entering the component. The significant amount of refrigerant liquid required to form the liquid seal can contribute to the initial and operating costs of the condenser because of the cost associated with refrigerant that cannot be used towards system capacity.